Journal of Volcanology and Geothermal Research最新文献

{"title":"Effects of lateral dyke propagation and pre-existing fractures on shallow deformation: Data from the Etna 1947 eruption and analogue models","authors":"A. Tibaldi ,&nbsp;A. Luppino ,&nbsp;E. De Beni ,&nbsp;N. Corti ,&nbsp;M. Cantarero ,&nbsp;F. Pasquarè Mariotto ,&nbsp;F.L. Bonali","doi":"10.1016/j.jvolgeores.2025.108349","DOIUrl":"10.1016/j.jvolgeores.2025.108349","url":null,"abstract":"<div><div>Mount Etna, one of Europe's most active volcanoes, has experienced a variety of eruption settings throughout its history, including summit, lateral, and eccentric eruptions. In this study, we provide a detailed analysis of the structures formed during the 1947 lateral eruption, along the NE Rift, using historical aerial photos and accounts, archival images, and contemporary field and drone data. Photogrammetric processing of 1932 and 1954 aerial photos enabled us to map the structures formed before and during the eruption, in order to examine the effects of pre-existing fractures on the 1947 deformation pattern. With the aid of field surveys, we studied 90 normal faults, 194 dry fractures and 17 eruptive fissures, collecting data on the structures' length, azimuth, vertical offset, vectors and amount of opening. The reconstruction of a detailed chronology of the eruption's day-by-day development, allowed us to characterize the event as a NE-directed, lateral propagation of magma along a N-S to NE-SW-striking dyke, which followed the path of a previous similar event. Based on the reconstruction of the fault-slip profiles at both sides of various 1947 grabens, we were able to show that fault scarps taper towards NE. Analogue models were also used to simulate the lateral intrusions of dykes and the consequent formation of shallow structures. All the data suggest that the formation of the various structures, with different geometry and deformation, depends upon a combination of magma overpressure, local topography, external stresses, pre-existing structures, and direction of magma propagation.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108349"},"PeriodicalIF":2.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143927840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeochemical characterization of mineral waters from Fogo Volcano (São Miguel, Azores)","authors":"L. Ferreira ,&nbsp;J. Virgílio Cruz ,&nbsp;F. Viveiros ,&nbsp;N. Durães ,&nbsp;C. Andrade ,&nbsp;N. Cabral ,&nbsp;J.F. Santos","doi":"10.1016/j.jvolgeores.2025.108348","DOIUrl":"10.1016/j.jvolgeores.2025.108348","url":null,"abstract":"<div><div>Mineral waters discharges of Fogo volcano (São Miguel Island, Azores) present a wide range of physico–chemical characteristics. These discharges may be divided into thermal waters, with temperatures as high as 58.4 °C and some with acidic pH (2.4–3.3), and cold waters, some of them with high dissolved CO₂ concentrations (maximum value = 1028 mg.L⁻¹). There is a negative correlation between pH and temperature, ascribed to volcanic input, and a positive correlation between electrical conductivity and the concentration in HCO₃, usually associated with rock weathering. These waters do not exhibit a significant seasonal variation of the major components and physico–chemical parameters. Nevertheless, rare earth elements and ⁸⁷Sr/⁸⁶Sr ratios point to an incongruent dissolution of the rock, with some samples depicting a seasonal influence, which is related to different proportions of rock weathering. Based on the analyzed samples and the subsurface geology, it was possible to distinguish different perched–aquifers systems in Fogo, associated to lava flows sequences. Caldeiras da Ribeira Grande is characterized by thermal and acid–sulfate waters, and Lombadas presents a shallower aquifer system, with high CO₂ influx and higher concentrations of rock–forming elements.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108348"},"PeriodicalIF":2.4,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining the timing and climate forcing of the Long Island (Papua New Guinea) and Tarumae (Japan) eruptions and other 17th century volcanic eruptions","authors":"Imogen Gabriel ,&nbsp;Helen M. Innes ,&nbsp;Peter M. Abbott ,&nbsp;Jörg Franke ,&nbsp;Melanie Behrens ,&nbsp;Nathan J. Chellman ,&nbsp;Maria Hörhold ,&nbsp;William Hutchison ,&nbsp;Joseph R. McConnell ,&nbsp;Birthe Twarloh ,&nbsp;Michael Sigl","doi":"10.1016/j.jvolgeores.2025.108346","DOIUrl":"10.1016/j.jvolgeores.2025.108346","url":null,"abstract":"<div><div>The 17^th century was a period when several major (VEI &gt; 5) tropical and extratropical volcanic eruptions occurred. Amongst these is the VEI 6 eruption of Long Island (Papua New Guinea), which is suggested to have occurred between 1665 and 1668 CE based on historical accounts, radiocarbon dating constraints, and an ice-core record from South Pole. Accepting such an attribution on the basis of this ice-core chronology would imply a hitherto undiagnosed dating error of up to 6 years during the 17^th century within all ice-core records from Antarctica. Here we constrain the timing of the Long Island eruption through tephrochronology and high-resolution glaciochemical measurements from an array of records from Antarctica and Greenland. We identify cryptotephra glass shards in association with the Greenland 1667 CE sulfate peak and geochemically attribute them to the historic Japanese Tarumae (Shikotsu) eruption. This attribution shows that the ice-core records are not misaligned during this period and refines the timing of the Long Island eruption to two candidate dates: 1654 ±1 CE and 1662 ±1 CE. Both candidate dates are within previous best age estimates based on radiocarbon dating (1651 and 1671 CE, 95.4 % probability). However, here we tentatively use 1662 ±1 CE as the timing of the Long Island eruption, as previous radiocarbon constraints suggest a 68.2 % probability of occurrence between 1655 and 1665 CE. With a higher confidence in the dating, we revised volcanic stratospheric sulfur injection (VSSI) estimates across the 17^th century. Using these alongside paleo-proxy records, we explored the Northern Hemisphere climate response to the Long Island and Tarumae eruptions and found them to be more limited compared to other major (VEI &gt;5) eruptions during this century. Ultimately, this study has highlighted the accuracy of ice core chronologies, having wider implications for volcanic forcing reconstructions and detection and attribution studies of natural climate variability.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108346"},"PeriodicalIF":2.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstructing the volcanic history of the Ulukışla Caldera: A collapse structure within the Hasandağ Volcanic Complex, Central Anatolia (Turkey)","authors":"Rengin Özsoy ,&nbsp;Ivan Sunyé-Puchol ,&nbsp;Xavier Bolós ,&nbsp;Efe Akkaş ,&nbsp;Antonio Costa ,&nbsp;Lorenzo Tavazzani ,&nbsp;Daniel P. Miggins ,&nbsp;Manuela Nazzari ,&nbsp;Olivier Bachmann ,&nbsp;Piergiorgio Scarlato ,&nbsp;Silvio Mollo","doi":"10.1016/j.jvolgeores.2025.108345","DOIUrl":"10.1016/j.jvolgeores.2025.108345","url":null,"abstract":"<div><div>The Ulukışla Caldera is a collapse structure within the active Hasandağ Volcanic Complex (Central Anatolia), situated along the southern branch of the Tuz Gölü Fault Zone (TGFZ). This study aims to reconstruct the volcanic history of the Ulukışla Caldera by characterising its associated pyroclastic deposits using tephrostratigraphy, glass chemistry (major and trace elements), and geochronological data (⁴⁰Ar/³⁹Ar and U-(Th)-Pb). Our findings reveal that the Ulukışla Caldera has undergone at least three major explosive rhyolitic eruptions, which formed the pyroclastic deposits of the Yenipınar Eruption (∼442 ka), the Belbaşhanı Eruption (∼400 ka), and the Ulukışla Eruption (∼326 ka). The Yenipınar unit was produced by an unsteady eruption column originating from paleo-Ulukışla volcanic structure, that deposited pumice fallout layers and interbedded pyroclastic density current (PDC) deposits. The Belbaşhanı Eruption began with a Plinian column that deposited the Belbaşhanı Pumice fallout. This phase was followed by the emplacement of thick PDC deposits and co-ignimbrite lithic lag breccias during the collapse, which ultimately led to the formation of the Ulukışla Caldera. The volume of the Belbaşhanı deposits, including the pumice fallout and the caldera-forming ignimbrite, could reach up to 10 km³ DRE (Dense Rock Equivalent), corresponding to an eruption of magnitude ∼6. The Ulukışla Pumice resulted from a post-caldera eruption, which did not generate PDCs. The Ulukışla Caldera exhibits an elongated morphology, which is strongly influenced by the NW-SE alignment of the TGFZ. Based on this morphology and the regional tectonic setting, we conclude that the Ulukışla Caldera is a strike-slip/graben caldera. Reconstructing the volcanic history of this newly identified caldera is essential for enhancing our understanding of the Hasandağ Volcanic Complex. Our findings offer valuable context for future eruptive behaviour, improving the hazards assessment for potential caldera collapses, and contribute to mitigating associated risks.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108345"},"PeriodicalIF":2.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial distribution of alteration and strength in a lava dome: Implications for large-scale volcano stability modelling","authors":"Agata Poganj ,&nbsp;Michael J. Heap ,&nbsp;Patrick Baud","doi":"10.1016/j.jvolgeores.2025.108344","DOIUrl":"10.1016/j.jvolgeores.2025.108344","url":null,"abstract":"<div><div>Volcanoes are unstable heterogeneous structures that can host hazardous mass movements. Hydrothermal alteration can create weak zones that promote instability. Volcanic instability can be assessed using large-scale numerical models, which require accurate and reliable physical and mechanical rock input parameters. Volcano stability models are often constructed using discrete zones that are assigned homogeneous parameters, rarely accounting for the heterogeneity of volcanoes. Given that the range and distribution of alteration and rock strength in volcanoes are likely highly variable, these factors should be carefully determined for accurate modelling. Here, we performed an integrated field and laboratory study. We examined a total of 544 variably altered andesites from seven sampling locations at La Soufrière de Guadeloupe (Eastern Caribbean). Based on a visual assessment, we assigned the rocks an alteration grade index, from 1 (least altered) to 5 (most altered), and measured the strength of rocks in the field using a point load tester. The alteration and strength distribution maps we provide highlight the extreme heterogeneity of a volcanic structure. We provide a method for direct on-site conversion from field to laboratory strength. We find that porosity and strength increase and decrease, respectively, as a function of increasing alteration. The most altered rocks were weak regardless of their porosity, suggesting that the alteration is the primary factor governing strength. We conclude that a volcano can be heterogeneous in terms of alteration and strength, between and within the discrete zones. Therefore, if possible, material property heterogeneity should be incorporated in future volcanic stability models.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108344"},"PeriodicalIF":2.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The fate of an extremely phenocryst-rich magma in producing small sub-Plinian plumes during the 17th and 30th April 2024 eruption of Mt. Ruang (North Sulawesi, Indonesia): The role of clast density","authors":"Indranova Suhendro ,&nbsp;Geri Agroli ,&nbsp;Gabriela Nogo Retnaningtyas Bunga Naen ,&nbsp;Muhammad Andriansyah Gurusinga ,&nbsp;Dini Nurfiani ,&nbsp;Friska Putri Ayunda ,&nbsp;Robinsar Jogi Yoshua Manullang ,&nbsp;Noriyoshi Tsuchiya","doi":"10.1016/j.jvolgeores.2025.108332","DOIUrl":"10.1016/j.jvolgeores.2025.108332","url":null,"abstract":"<div><div>After ∼22 years of dormancy, two vigorous sub-Plinian eruptions occurred at Mt. Ruang (North Sulawesi, Indonesia) on April 17th and 30th 2024, with an observed plume height of 9–12 and 19 km, respectively. Petrography and whole-rock XRF analysis reveal that Ruang pumices are extremely rich in phenocrysts (0.36–0.87 <span><math><msub><mi>ф</mi><mi>PC</mi></msub></math></span>; plagioclase&gt;amphibole&gt;pyroxenes&gt;olivine&gt;oxides) and dense (1.31–2.33 g/cm³), with SiO₂ contents of 54.0–56.3 wt%. This suggests that the eruption was sourced by an extremely crystal-rich basaltic-andesite magma reservoir. The magma likely received substantial recharge from the deeper-hotter source as evidenced by the prevalence of amphibole megacryst, crystal clots, and disequilibrium phenocryst textures (i.e., reverse zoning, oscillatory zoning, and fine sieves). Ash from the 17th and 30th April 2024 eruptions are classified as very fine ash (median of 29 and 26 μm, respectively) and exhibit a blocky characteristic (0.75–0.99 convexity and 0.71–0.98 solidity). This evidence, coupled with the presence of stepped surface and hackle marks textures strongly suggests the involvement of external water during the eruption. The fact that Ruang pumices are characterized by high matrix-vesicle and feldspar microlite number density values (log ∼15 m⁻³) suggests that the magma decompression was rapid, reaching 0.05–27 MPa/s. However, despite this condition, the eruption was only able to generate relatively small sub-Plinian plumes. By consulting with the huge dataset from other previous studies, we found that plume height shows a negative correlation with phenocryst content and bulk density, with Ruang pumices having the highest phenocryst content and bulk density variations. This suggests that; besides magma decompression rates and magma-water interaction, the pre-eruptive crystallinity condition within the magma reservoir is essential for controlling the plume height and hence might be used as a proxy to predict the intensity of future eruptions.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108332"},"PeriodicalIF":2.4,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complex principal component analysis of volcanic earthquakes at Azuma volcano, Japan, recorded by a distributed acoustic sensing system (DAS) for the hypocenter determination","authors":"Takeshi Nishimura ,&nbsp;Fumiya Morisaku ,&nbsp;Kentaro Emoto ,&nbsp;Hisashi Nakahara ,&nbsp;Mare Yamamoto ,&nbsp;Satoshi Miura","doi":"10.1016/j.jvolgeores.2025.108343","DOIUrl":"10.1016/j.jvolgeores.2025.108343","url":null,"abstract":"<div><div>Distributed Acoustic Sensing System (DAS) can record ground motions with a measurement interval of a few to ten meters for a long-distance range of a few tens of kilometers. The sensor, which is a fiber-optic cable embedded underground, is protected from damage caused by lightning or pyroclastic materials. These features are useful for the seismic observation of active volcanoes. We analyzed DAS data recorded at the Azuma volcano, Japan, to determine the location of volcanic earthquakes and evaluate their reliability. Using the benefits of highly dense measurement points along the fiber optic cable, we applied complex principal component analysis (CPCA) to measure the arrival time differences of seismic waves from volcanic earthquakes. We used a relative hypocenter determination technique to accurately determine the source locations of the volcanic earthquakes recorded during our observation period in July 2019. We observed 148 small volcanic earthquakes and succeeded in determining 31 events with sufficient arrival time difference data. The obtained source locations were distributed around Jododaira, extending in the north-south direction with a length of approximately 2 km. These regions are consistent with the hypocenters determined from standard hypocenter determination using the arrival times of the P- and S-waves of volcanic earthquakes from 2017 to 2022. We also determine the source locations by using the arrival time difference measured by the cross-spectral method, which is often used in seismic wave analyses, and the number of located events is small and the obtained source locations are scattered. These results suggest that CPCA is useful for extracting signals from noisy raw seismic data and accurately measuring the arrival time difference for the source locations.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108343"},"PeriodicalIF":2.4,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of the crustal reservoir feeding La Palma 2021 eruption. Insights from phase equilibrium experiments and petrologically derived time scales","authors":"J. Andújar ,&nbsp;B. Scaillet ,&nbsp;D. Frascerra ,&nbsp;I. Di Carlo ,&nbsp;R. Casillas ,&nbsp;E.D. Suárez ,&nbsp;I. Domínguez-Cerdeña ,&nbsp;S. Meletlidis ,&nbsp;C. López ,&nbsp;A. Slodczyk ,&nbsp;J. Martí ,&nbsp;E. Núñez-Guerrero","doi":"10.1016/j.jvolgeores.2025.108327","DOIUrl":"10.1016/j.jvolgeores.2025.108327","url":null,"abstract":"<div><div>Crystallization experiments were performed on three representative samples of the 2021 La Palma eruption at variable temperatures (920–1150 °C), pressures (100–400 MPa), and H₂O-CO₂ ratios in order to shed light on the pre-eruptive reservoir architecture and evolution. Experimental data reveal that La Palma crustal reservoir was at 300 MPa (10 km), at a temperature of 1065 °C with a melt water content of 2–3 wt%, lying in the stability field of amphibole. Mineral compositional zoning along with experimental constraints and whole rock data, show that a cold magma body (850–950 °C), likely a remnant of previous eruptive episodes at La Palma, was rejuvenated by hotter magmas that increased the temperature of the bottom portion of the reservoir up to 1135 °C. Time scales derived from olivine diffusion profiles show that such a reactivation started 10–15 years prior to eruption, and was marked by at least four different injections from a deep mantle reservoir at ≥25 km. This sequence is corroborated by geophysical signals and changes of surficial fluid geochemistry monitored during that period. Olivine zoning further indicates that the last mafic recharge prior to eruption onset occurred in mid-October 2018, and was followed by a post-injection cooling phase which continued up to the date of the eruption, during which the top portion of the rejuvenated body re-entered the stability field of amphibole. This cooling period preceding the eruption could in part explain the absence of pre-eruptive seismic signals at ∼10 km, as revealed by the revision of the precursory seismic catalogue since 2017. Once initiated, the eruption drained the 300 MPa body, which in turn activated the deep-seated mantle reservoir, lying at &gt;500–600 MPa, which supplied fresh, hotter and volatile-rich magma, that was emitted during the second half of the eruptive episode. Amphibole breakdown documented in first emitted magmas is related to decompression and not to overheating of the resident magmas. The fact that the rocks emitted during the first half of the eruption do not bear textural or compositional evidence for a mafic recharge occurring a short time prior the eruption suggest that the eruption triggering is linked to the internal evolution of the reservoir (volatile build-up) or to external factors.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108327"},"PeriodicalIF":2.4,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The 70 ka ‘Perote Pumice’ inter-caldera dacite-rhyolite Plinian eruption of Los Humeros Volcanic Complex, Mexico: Lithostratigraphy, hazards, and eruption dynamics","authors":"Rafael Torres-Orozco ,&nbsp;José Luis Arce ,&nbsp;Gerardo Carrasco-Núñez ,&nbsp;Ricardo Tlalpachito-Palomino","doi":"10.1016/j.jvolgeores.2025.108340","DOIUrl":"10.1016/j.jvolgeores.2025.108340","url":null,"abstract":"<div><div>Volcanic calderas span diverse eruptive styles, magnitudes, and intensities, comprising effusive/explosive activity often wrapped in between catastrophic caldera-forming episodes. During the inter-caldera stages, frequent Plinian eruptions, fueled by chemically varied magmas, pose significant hazards. The basaltic-rhyolitic Los Humeros Volcanic Complex (LHVC), Mexico's widest active caldera system, typifies such dynamics. The 70 ka Perote Pumice (PP), the largest eruption during LHVC's inter-caldera period (164–69 ka), marks a critical phase of high-intensity volcanic activity following the main caldera-collapse (164 ka). Here, we integrate lithostratigraphic mapping (52 locations) with geochemical and microtextural analyses to reconstruct the PP eruption source parameters, hazards, and dynamics. Our findings indicate that the PP deposits, comprising 13 layers (8 fallout and 5 pyroclastic density currents) reflect progression from dacite unsteady plumes and outgassed lava-plug bursts to a sustained gas-rich rhyolite-driven Plinian column, culminating in column-collapse due to waning gas and magma supply. This catastrophic VEI-6 eruption produced 30–40 km-high columns, 4.73 ± 0.18 km³ DRE, and maximum 9 × 10⁸ ± 0.9 kg s⁻¹, depositing pumice from proximal (∼1360 km²) to distal offshore areas (max. 200 km from the source to the Gulf of Mexico). The geochemical and microtextural data suggest that both dacite and rhyolite magmas mingled, were rapidly decompressed, and fragmented, yielding pervasive banded pumice. The refined stratigraphy, eruption parameters, and dynamics underscore PP as a benchmark for high-intensity inter-caldera volcanism. Considering LHVC's potential for future silicic activity, a PP-scale event would threaten two-million people within 140 km east and southeast of the caldera.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108340"},"PeriodicalIF":2.4,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The link between geothermal resources and subsurface geological structures in the magma-rich Ethiopian rift: A case study of the Boku geothermal prospect","authors":"Habtamu Wuletawu ,&nbsp;Abera Alemu ,&nbsp;Wubamlak Nigussie ,&nbsp;Kevin Mickus ,&nbsp;Derek Keir ,&nbsp;Simeneh Wassihun ,&nbsp;Shimelis Wendwesen","doi":"10.1016/j.jvolgeores.2025.108333","DOIUrl":"10.1016/j.jvolgeores.2025.108333","url":null,"abstract":"<div><div>In the volcanically and tectonically active zones of the main Ethiopian Rift, geothermal resources are primarily influenced by subsurface geological structures along the rift valley floor which contains multiple volcanic complexes. However, the specific subsurface structures of these volcanic systems and their relation to the distribution of shallow geothermal resources remain inadequately understood. This study utilizes gravity data from the Global Gravity Model Plus2013 and ground magnetic data to investigate the role of subsurface volcanic features in the occurrence of geothermal resources within the Boku Geothermal Prospect (BGP). Interpretation of gravity and magnetic anomalies, along with derivative maps, suggests the presence of a potential geothermal heat source beneath the Boku geothermal area. The 2D joint gravity and magnetic models, combined with gravity and magnetic anomalies, indicate a dense mafic intrusion at approximately 4.5 km depth beneath the BGP, which is likely the heat source for the geothermal system. Linear features (trending NNE-SSW and NE-SW), interpreted as faults and weak zones from derivative maps, appear to play a crucial role in hydrothermal circulation by acting as conduits for transporting hydrothermal fluids, facilitated by these faults and weak zones. Our 2D models reveal interactions between Quaternary faults within the Wonji Fault Belt (WFB) and the subsurface mafic intrusion, elucidating the mechanism by which thermal heat is transported to the shallow subsurface and surface. The surface thermal manifestations are strongly correlated with the structures detected by Horizontal Derivative and Analytic Signal analyses, indicating that the BGP area is structurally controlled. This complex faulting system provides extensive permeability and favorable conditions for the occurrence of geothermal resources within the BGP.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108333"},"PeriodicalIF":2.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}